Rebalancing apparatus for translating an electrical signal to a symbolic display



Dec. 9, 1969 F. s. GOWER m 3,483,554

- REBALANCING APPARATUS FOR TRANSLATING AN ELECTRICAL SIGNAL To A SYMBOLIC DISPLAY Filed March 25, 1968 4 Sheets-Sheet l er 3% W Mgflw 1969 F. B. GOWER m 3,483,554

REBALANCING APPARATUS FOR TRANSLATING AN ELECTRICAL SIGNAL TO A SYMBOLIC DISPLAY 4 Sheets-Sheet 2 Filed Marh 25, 1968 Dec. 9. 1969 F. B. GOWER m 3,483,554

REBALANCING APPARATUS FOR TRANSLATING AN ELECTRICAL SIGNAL TO A SYMBOLIC DISPLAY Filed March 25, 1968 4 Sheets-Sheet 5 Dec. 9. 1969 B, gowE 3,483,554

; REBALANCING APPARATUS FOR TRANSLATING AN ELECTRICAL SIGNAL TO A SYMBOLIC DISPLAY Filed March 25, 1968 4 Sheets-Sheet 4.

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United States Patent US. Cl. 340366 Claims ABSTRACT OF TIE DISCLOSURE A device for translating an electrical signal to a symbolic display. In the illustrative embodiment, the electrical signal causes movement of the vane of a galvanometer. The vane is normally blocking a predetermined portion of the light directed from a lamp to a photocell, which is an element of a motor energizing circuit. Upon movement of the vane, the change in the amount of light impinging on the photocell will change the resistance of the photocell, causing the motor to be energized. The energized motor causes the photocell to be driven toward the vane until once again, the vane blocks a predetermined portion of the light directed toward the photocell. A disk having numbers thereon is rotated in conjunction with movement of the photocell, and the numbers on the disk passing a predetermined location are projected to a viewing screen.

This invention relates to a device for translating an electrical signal to a symbolic display. Although the illustrative embodiment of the invention concerns a digital readout apparatus, the present invention can be utilized when the display of any type of symbol is desired in response to a variation in an electrical signal.

Digital readout equipment is in wide use today, although generally such equipment is considered relatively expensive. The present invention provides digital readout apparatus which is relatively simple in construction and economical to manufacture.

In accordance with the present invention, digital readout apparatus is provided having an input for receiving an electrical signal. Control means, movable in response to receipt of the electrical signal, are provided. A photo sensitive device is positioned adjacent the control means, and the photo-sensitive device is movable in a plane parallel and adjacent to the plane in which the control means moves.

A lamp for directing a beam of light to the photo-sensitive device is connected to the photo-sensitive device, in order to be movable therewith. An electrical motor, which is controlled in accordance with the position of the control means with respect to the photo-sensitive device, is provided for driving the photo-sensitive device and the lamp.

A disk having digits thereon is provided and is movable in conjunction with movement of the photo-sensitive device. Movement of the control means will cause actuation of the motor, thereby causing the photo-sensitive device to follow the control means. During travel of the photo-sensitive device, the disk will move, causing the digits to pass a predetermined location, at which location a projection system is provided. The digits passing the projection system will be projected on a viewing screen.

When the photocell has reached its normal position with respect to the control means, the motor will be deenergized, thereby discontinuing movement of the photosensitive device and the disk.

In the illustrative embodiment of the invention, the control means comprises the vane of a galvanometer,

which vane is moved in accordance with the signal to the galvanometer. A motor energizing circuit having a silicon controlled rectifier is provided for controlling the energization of the motor. The photo-sensitive device is con nected in the gate circuit of the silicon controlled rectifier, whereby movement of the control means with respect to the photo-sensitive device causes a variation in the signal at the gate of the silicon controlled rectifier.

In the illustrative embodiment, the projecting means includes a lamp located on one side of the disk and a lens located on the other side of the disk. The light emitted by the lamp is directed through the disc and via the lens, to a mirror for reflecting the image from the lens to the viewing screen.

A more detailed explanation of the invention is provided in the following description and claims, and is illustrated in the accompanying drawings, in which:

FIGURE 1 is a perspective view of a digital readout apparatus according to the principles of the present invention;

FIGURE 2 is a cross-sectional top plan view of the electrical circuit portion of the apparatus illustrated in FIGURE 1;

FIGURE 3 is a sectional elevation of the apparatus of FIGURE 1, taken along the lines 33 of FIGURE 4;

FIGURE 4 is a sectional view of the apparatus of FIgillRE 1, taken along the lines 4-4 of FIGURES 1 an FIGURE 5 is a sectional elevation of the apparatus of FIGURE 1, taken along the lines 55 of FIGURE 4;

FIGURE 6 is a sectional view taken along the lines 6-6 of FIGURE 5;

FIGURE 7 is a sectional view taken along the lines 7-7 of FIGURE 3; and

FIGURE 8 is a schematic circuit diagram of a motor energizing circuit in accordance with the principles of the present invention.

The apparatus comprises a base 10, a central housing 12 connected to the base 10, and a viewing screen housing 14 connected to the central housing 12. The viewing screen housing 14 has a viewing screen 16 positioned therein and the base 10 has electrical wires 18 extending therefrom and an off-on switch 20 connected thereto.

The elements forming the basic electrical circuit, which circuit is described in detail below, are connected to the base 10. These elements include resistors 21, 22, 23 and 24, which resistors are fastened to a circuit board 25. A full wave rectifier 26 and a silicon controlled rectifier 27 are also fastened to the circuit board 25. The circuit elements also include potentiometers 28 and 29, a transformer 30, input connectors 32 and 33, switch 20 and lines 18 for connection to a current supply.

Within the central housing 12 there is positioned a conventional galvanometer 38 having a vane 40 and magnetic core 42. The galvanometer 38 is electrically coupled to input connectors 32 and 33 and is responsive to the electrical signal that is applied thereto.

As seen in FIGURE 4, the end portion 44 of the vane 40 has a generally tear-drop shape defining a large surface area. End portion 44 is utilized to regulate light received by a photocell, as will be described below.

Within the housing 12 there is positioned a support plate 46 to which a disk 48 (see FIGURES 4, 5 and 6) is pivotally connected by a pivot pin 50. The periphery of the disk 48 is toothed, and the teeth 52 engage the teeth 54 of a gear 56 which is keyed to a shaft for rotation therewith. Toothed disk 58 is also keyed to shaft 60 and is driven by a gear 62 which is fastened to a shaft 63. Also fastened to the shaft 63 is a gear 64 which is driven by gear 66 which is keyed to the shaft 68 of an electrical motor 70. Hence, rotation of motor shaft 68 causes rotation, respectively, of gears 66, 64, 62, 5 8, 56 and disk 48.

An arm 72 fastened to disk 48 for rotational movement therewith. Fastened to the end of arm 72 is an arrangement including a photocell 74 and a lamp 76 which directs a beam of light to the photocell 74. The photocell 74 and lamp 76 are spaced by Wire support members 78 in a manner so that the vane 40 of the galvanometer 38 can be interposed between the lamp 76 and the photocell 74 with the end portion 44 of the vane 40 blocking a portion of the light directed from the lamp to the photocell when the vane is so interposed.

An opaque disk 82 having light transmissive numbers 84 thereon is affixed to the underside of the toothed disk 58. Underlying the disk 82 is a lamp 84 and a lens 86, and overlying the supporting plate 46 is a lens member 88 having a lens therein which is aligned with the lens 86. Toothed disk 58 is formed of a light transmissive plastic material and the separating plate 46 defines a slot 90 (FIGURE 3) through which the light emitted by lamp 84 can pass. The numerals 84 are formed on the opaque disk 82 in a manner so that they will directly overlie the lamp 84 and lens 86 and the light emitted from the lamp 84 will be transmitted via lens 86 through the light transmissive numeral, and through the slot 90 via the lens within lens member 88, and upwardly to a mirror member 94 connected to the housing 12 by a bracket 96. The mirror member 94 is positioned so that its reflective surface will reflect the image from lens member 88 to the viewing screen 16, as shown most clearly in FIGURE 3.

The lens member 88 is connected to an extension 98 which is fastened to a pivot 100 to which an extension 102, carrying lens 86 and lamp 84, is also fastened. The slot 90 is elongated so that lens member 88, lens 86 and lamp 84 can be pivoted and the light will remain directed through the slot. In this manner, light transmissive numerals can be presented at different radii on the opaque disk 82, in order to provide different calibrations.

In the operation of the apparatus, movement of the vane 40 in response to an electrical signal will cause a change in the amount of light directed upon photocell 44 from lamp 76. This will cause the electrical motor 70 to be energized and the numbered disk 82 will rotate until a predetermined amount of light from lamp 76 impinges upon photocell 74. In other words, once the photocell and lamp are again in a predetermined position with respect to the vane, the motor will be de-energized and the numbered disk 82 will discontinue rotation. At that time, one of the numerals on the disk 82 will be located above the lamp 84 and its image will be directed via the lenses and mirror 94 to the viewing screen 16. The operator will see a digital readout presented on the viewing screen 16, which readout is calibrated in proportion to the electrical signal applied at the input 32 and 33.

The motor control circuit is illustrated in FIGURE 8. A transformer 30 is connected to input lines 18 to provide six volts at the secondary. A DC motor 70 is connected to one side of the secondary of transformer 30 and a full wave rectifier 26 is connected between the DC motor and the other side of the transformer secondary. Connected across the output of full wave rectifier 26 is a silicon controlled rectifier 27 having a resistor 24 connected between its cathode and gate. A potentiometer 29 and a resistor 23 are connected between the gate of the silicon controlled rectifier 27 and a point 98 on a bridge which is formed by connecting photocell 74 and resistor 22 across the transformer secondary. The lamp 76 and resistor 21 are also connected across the output of the transformer.

An input signal is applied to terminals 32 and 33 which are coupled to the galvanometer 38, which has a vane 40 that moves in response to the signal applied, as described above. The circuit components are such that when a predetermined amount of light directed to photocell 74 by lamp 76 is blocked by end portion 44 of the vane 40, the motor will not be energized. This null condition will exist when the resistance of photocell 74 is equal to the resistance of resistor 22.

When the end portion 44 of the vane 40 blocks all the light to the photocell 74 from lamp 76, the resistance of the photocell will increase causing the bridge to be unbalanced and the motor will turn in a first direction. When end portion 44 allows more light than a predetermined amount to reach the photocell 74 from lamp 76. the decrease in resistance of the photocell 75 will again cause an unbalance of the bridge, resulting in the motor turning in a direction opposite to the first direction. As stated above, lamp 76 and photocell 74 are moved by rotation of the motor, and when the lamp and photocell are positioned so that a predetermined amount of light from lamp 76 is impinging upon photocell 74, the null condition will again exist and the motor will be deenergized.

As a specific example, the following elements were used in the illustrative embodiment of the invention. However, no limitation is intended with respect to the following elements, as other equivalent elements may be substituted and utilized.

Value or Component: model number SCR 27 2N2322.

Resistor 24 2.2K,

Potentiometer 29 5K max.

Resistor 21 15 ohms.

Resistor 22 6.8K.

Resistor 23 3.3K.

Lamp 76 GE No. 39 lamp.

Photocell 74 Raytheon 1502.

What is claimed is:

1. A digital readout apparatus which comprises: input means for receiving an electrical signal; control means movable in response to receipt of said signal; means for driving said control means; a photo-sensitive device movable in a plane parallel and adjacent to the plane in which said control means moves; means for directing a beam of light to said photo-sensitive device, said beam directing means being movable with said photo-sensitive device: means for driving said photo-sensitive device and said beam directing means; means for actuating and deactuating said driving means, said actuating and deactuating means being controlled by the position of said control means with respect to said photo-sensitive device; means having digits thereon, said last-mentioned means being movable in conjunction with movement of said photosensitive device; and means for viewing said digits.

2. Digital readout apparatus as described in claim 1, wherein said control means comprises the vane of a galvanometer.

3. Digital readout apparatus as described in claim 1, said photo-sensitive device driving means comprising an electrical motor; said actuating and deactuating means including a motor energizing circuit having a silicon controlled rectifier for controlling the energization of said motor; said photo-sensitive device being connected in the gate circuit of said silicon controlled rectifier, whereby movement of said control means with respect to said pho- 'to-sensitive device causes a Various of the signal at the gate of said silicon controlled rectifier.

4. Digital readout apparatus as described in claim 3. wherein said control means comprises the vane of a galvanometer.

5. A device for translating an electrical signal to a symbolic display, which comprises: means for receiving said electrical signal; an electro-mechanical transducer having a member movable in proportion to the intensity .of said electrical signal; a photo-sensitive device; a lamp; said photo-sensitive device and said lamp being connected whereby the light emitted by said lamp is directed toward said photo-sensitive device; means for driving said photosensitive device along a path parallel to the plane of travel of said member; said photo-sensitive device and said lamp being located in planes on opposite sides of the plane in which said member is located whereby said member nor mally blocks at least some of the light emitted by said lamp toward said photo-sensitive device thereby causing less light to impinge on said photo-sensitive device when said member is in its normal position; a disk operatively connected to said photo-sensitive device for rotation therewith, said disk having symbols thereon; an output viewing screen; means for projecting said symbols to said viewing screen, said projecting means being located at a predetermined position with respect to said disk whereby the symbol adjacent said predetermined position will be projected to said viewing screen; control circuit means for controlling said photo-sensitive device driving means, said control circuit means being responsive to the light received by said photo-sensitive device, whereby movement of said member out of the path of said light beam directed to said photo-sensitive device will cause said photo-sensitive device driving means to be energized resulting in movement of said photo-sensitive device toward the member, and when said photo-sensitive device reaches said member and said member is blocking at least some of the light emitted by said lamp toward said photo-sensitive device, said photo-sensitive device driving means will be de-energized.

6. A device for translating an electrical signal to a symbolic display as described in claim 5, said disk comprising an opaque element having light transmissive symbols thereon, said projecting means including a lamp located on one side of said opaque element and a lens located on the other side of said opaque element.

7. A device for translating an electrical signal to a symbolic display as described in claim 5, said projecting means including a lamp located on one side of said disk, a lens located on the other side of said disk, the light emitted by said lamp being directed toward said lens; and a mirror for reflecting the image from said lens to said viewing screen.

8. A device for translating an electrical signal to a symbolic display which comprises: input means for receiving said electrical signal; control means movable in response to said signal; a photo-sensitive device; a lamp connected to said photo-sensitive device for movement therewith; a symbol carrying device operatively connected to said photo-sensitive device; means for driving said symbol carrying device, said driving means being energized in response to movement of said control means with respect to said photosensitive device and de-energized in response to a predetermined position of said control means with respect to said photo-sensitive device; and projection means for projecting symbols at a selected location to a viewing device.

9. A device for translating an electrical signal to a symbolic display as described in claim 8, said symbol carrying device driving means comprising an electrical motor; said actuating and deactuating means including a motor energizing circuit having a silicon controlled rectifier for controlling the energization of said motor; said photo-sensitive device being connected in the gate circuit of said silicon controlled rectifier, whereby movement of said control means with respect to said photo-sensitive device causes a variation of the signal at the gate of said siliconcontrolled rectifier.

10. A device for translating an electrical signal to a symbolic display as described in claim 8, wherein said control means comprises the vane of a galvanometer.

References Cited UNITED STATES PATENTS 1,072,426 9/1913 Claflin 340378.2

JOHN W. CALDWELL, Primary Examiner HAROLD I. PI'ITS, Assistant Examiner 

